The present invention is directed to a device for firstly storing a supply of dental floss, and thereafter paying it out to form three separately-usable strips of floss, each strip being used for flossing by itself. Dental floss supply and strip-provision means are known, an example of one being disclosed in U.S. Pat. No. 4,151,851, to Bragg. Other devices are known, but all suffer from the disadvantage that proper tensioning of the floss to be used is difficult to achieve in combination with the paying out of the floss from the supply. Such tensioning of the floss for use has hitherto been achieved only by the use of two hands of the user, making it time-consuming, difficult, and, at times, frustrating. Further, prior art devices have only provided one, relatively short length of floss for use, that is quickly used up, with the necessity of advancing the floss to bring a new, fresh portion to the area where it may used.